I had exactly the same problem as the OP.
My ex-husband and I divorced 23yrs ago, he was never interested in anything like fb or friends reunited so I never realised I would have anything to worry about until about 9yrs ago when my son was contacted by a cousin who'd said my ex wanted to make contact with him and passed on the fact that he was now on fb.
My son wasn't keen on talking to his father but looked at his fb page all the same and saw that he had added a number of photos to it, including some of our wedding pictures!
A bit of back story.... several years earlier my ex had sent me a letter enclosing all copies of any photos he had of me and/or our son, saying he'd rather not have them as a reminder because my son had said he wanted nothing to do with him (he'd had precious little input over the years anyway).
He came straight to me, angry that his father would blatantly put pics of ME on his page especially as we'd had no contact for years.
My son spoke to his cousin and eventually got in touch with his father and told him in no uncertain terms that he did not have our permission (his or mine) to post these pictures and that he must remove them.
He refused point blank to take them down.
I eventually went to fb whilst my son spoke to his cousins, aunts and uncles, all in an attempt to get these pictures removed. Even his family couldn't understand why he'd want pictures of me on his page but no amount of persuasion would make him take them down.
My efforts with fb fell on deaf ears too, they said that these pictures were 'a part of his life and he has the right to display them if he wants to'. I argued that it was also my right NOT to have them displayed without my permission, not least the fact that they'd been taken in 1995, we'd divorced in 1998 and the ex hadn't even created his fb page until 2012, so why did he feel the need to put them up anyway?
Long story short, no matter what we did, we couldn't get them removed. Fb did say that if I felt 'that' strongly about it I could take the ex to court to get them removed.... my son and I have agreed that he's not worth the time, cost or effort, so we've blocked his fb page so that we don't have to see my pics, my son totally blanks his father if he sees him in the street and refused to talk about him if he speaks to his cousins. Totally blank him out, prove he means nothing to us, that's what we've found to be the best course of action.